cluster click event in chrome

We are using the arcgis javascript 3.15 api but a cluster click event is not firing in Chrome for some reason. It fires the click event on IE though. Clicking outside the cluster circles works as expected (it zooms in) in both IE and Chrome. IE Debugger shows that when a cluster circle is clicked, line 3377 of init.js "return a[f].apply(a, arguments || []);" is supposed to be executed but obviously this is not happening in Chrome. Clicking any circles in Chrome does not trigger to execute any javascript api codes at all. We tried the version 3.23 but with no luck. Please advice.

We are developing using c#/asp.net/mvc/.net framework 4. We are referencing the CDN version api at https://js.arcgis.com/3.15/ ; we are also using the latest Chrome.

1. screenshot of IE Debugger showing which line in init.js to be executed when the circle is clicked

2. our map with clusters; clicking any circles will not fire any events in Chrome but works fine in IE